Fusariosis: causes, symptoms, diagnosis, and treatment

Fusariosis is a cutaneous, corneal, or systemic infection caused by fusarium, which is a fungus widely distributed in nature, mostly saprophytic, and is prone to invade grains in the field and various cereals stored in warehouses.


Causes

Fusarium is a conditional pathogen. Individuals with skin wounds or decreased immunity are susceptible to fusariosis. Common pathogens are fusarium moniliforme, fusarium solani, and fusarium oxysporum. Fusarium is one of the most common pathogens that cause keratitis and corneal ulcers, and can also cause endophthalmitis, osteomyelitis, arthritis, sinus infections, onychomycosis, and mycetoma. Fusarium can reproduce in scabs and tissue debris on burned skin, but generally does not invade peripheral tissues, and can occasionally cause disseminated infection.


Signs and Symptoms

The main symptoms are obvious fatigue, headache, dizziness, vomiting, diarrhea, and severe disorders of the central nervous system. There is an alimentary toxic aleukia mainly caused by strong toxins derived from fusarium sporotrichioides and fusarium poae invading grains in the field in winter. Fusarium tricinctum can produce a metabolite termed T-2 toxin, which can cause necrosis of bone marrow hematopoietic tissue and hemorrhage of internal organs. Fusarium can also cause systemic diseases, invading the urethra, bladder, brain, kidney, lung, heart, bone, and pancreas. Disseminated infections are more common in patients with neutropenia or bone marrow transplantation.


Histopathology

Granuloma with different sizes and morphologies can be seen in skin lesions. Central necrosis, infiltration of neutrophils, histiocytes, and multinucleated giant cells, fusarium scattered in these cells, and sometimes lymphocytes infiltration can be seen. Fusarium is round or oblong, 4μm × 10μm in size, and the spores can be light blue stained. Branched, septate hyphae, and macroconidia or microconidia can be seen in GMS stain.

Figure 1 fusarium solani in microscopy

Figure 2 chlamydospore of fusarium solani in microscopy

Figure 3 macroconidia of fusarium solani in microscopy

Figure 4 microconidia of fusarium solani in microscopy


Diagnosis

On the basis of clinical presentations and hyphae or spores found in histopathology or microscopy, the disease can be diagnosed.


Treatment

Persistent neutropenia helps spread of the disease, while correction of neutropenia helps the treatment.

Amphotericin B 1.0 - 1.5 mg/(kg.d) can be administered, and amphotericin B lipid preparations can be used in patients who cannot tolerate amphotericin B.

Surgery can be used to excise local infections.

Itraconazole, fluconazole, and terbinafine may be effective.